An analysis of human papillomavirus testing and endocervical component on pap tests: A pilot study using the Roche Cobas® assay

Introduction HPV is known to have a predilection for infecting the transformation zone (TZ). Endocervical cells (EC) on a Pap test (PT) indicate that the cervical TZ has been sampled. Earlier repeat testing of women lacking EC is of little value in further detecting disease, thus a sample without EC is not necessarily inadequate. Both HPV testing and PT can be performed using a single sample; however, few studies have investigated the relationship between HPV results and TZ sampling. Materials and Methods Specimens were collected following the ThinPrep® liquid-based PT protocol. The Roche Cobas® HPV test was performed on post-aliquot samples. Data was collected retrospectively on 500 patients: 250 consecutive cases of EC- and 250 of EC+ on PT. To maintain uniformity, we included only cases diagnosed as negative (NILM). We compared HPV test results within each category. As a positive control, five consecutive cases each of LSIL and HSIL were also reviewed. Results Of NILM cases, 11 of 250 EC+ cases and 14 of 250 EC- cases were positive for hrHPV. HPV 16 was present in 5 of 11 EC + cases and in 1 of 14 EC- cases. Of LSIL cases, 1 of 5 EC+ cases was positive for hrHPV, and 2 of 5 EC- cases were positive for hrHPV. Of HSIL cases, 5 of 5 EC+ cases were hrHPV+. In the time period studied, only one case of EC- HSIL was found, which was positive for hrHPV. Discussion Although our study did not prove a significant correlation between HPV testing results and EC on PT, more EC+ PTs were positive for HPV16 compared to EC- PTs. The absence of EC on PT does not appear to warrant re-testing for HPV infection, though larger studies are required to determine the significance of low HPV 16 in PT without EC.